3. How can we keep things cold?
Many of the problems that we face and decisions that we make in everyday life require some basic understanding of scientific principles. In Activity 3 you will support your students in thinking carefully about a problem that they face everyday. There is no right answer to the problem and some groups of students will be more successful than others in providing a solution. Resource 5 gives you some background information on the problem. This is an opportunity to encourage your students to write about their experiment in their own words. It is important for your students to develop their literacy skills in school, and this doesn’t have to be in English or social studies classes. Resource 6 provides a writing frame which will help your students to structure their ideas clearly. You should let your students look at and comment on each other’s solutions. Case study 3 shows how Mrs Ussaman organised the activity as a competition.
Case study 3: Organising an investigation
Mrs Ussaman had been teaching physics for a few years and found that when she related the ideas she was teaching to everyday life, her students were much more interested. When she started teaching about heat, she asked her colleagues at school to give her pieces of cardboard, material and plastic that they didn’t need. By the time she came to the end of the topic she had a large collection.
One morning she gathered her class around the front and showed them a cup of ice cold soda. She challenged them to find a way of keeping it cold for as long as possible. The students worked in groups of five or six and made a plan. Mrs Ussaman gave them 30 minutes to plan and make their design. She gave each group a small piece of card and asked them to write a few sentences to explain how their design worked. She managed to borrow some alcohol thermometers from the local senior high school. Each group was given some water and two ice cubes. They measured the temperature of the water and recorded their reading.
The science lesson was at the start of the day, so the class gathered at lunchtime to measure the temperature of their cup of water and to look at each other’s designs. Mrs Ussaman asked the headteacher to present a small prize to the winning group. They had dug a hole in the ground for their cup and made a lid from a piece of plastic bubble-wrap. The group that came second had wrapped their cup in a wet towel.
Activity 3: Carrying out an investigation
In the weeks before you do this activity, you will need to collect waste materials such as cardboard, plastic, cotton and paper. When you have taught your students about heat transfer, set them the task of designing a way of keeping water cool as long as possible. They should work in groups and plan their design before they start to make it. Encourage them to think about how heat is transferred and to apply their knowledge and understanding to solve the problem.
When they have a plan, provide them with a cup of cold water and the materials that you have collected so they can make and test their design. At the end each group should display their design and explain why it works. Resource 6 provides guidance for your students to help them write a report on the problem and their solution.